This invention relates to a crash attenuator suitable for mounting to the end of a barrier, such as a roadside highway median barrier.
Exposed, unprotected ends of a median barrier, such as a concrete median barrier, present a hazard to an oncoming vehicle. In the past, several approaches have been used to protect motorists in oncoming vehicles from such barrier ends.
Sacrificial inertial crash attenuators have been used, which include a frangible container containing a dispersible material such as sand. See for example, U.S. Pat. Nos. Re 29,544 (Fitch), 4,289,419 (Young) and 4,934,661 (Denman). This approach is well recognized for its effectiveness. The relatively large mass of the dispersible material makes it difficult for a small number of personnel to install or replace a damaged inertial crash attenuator quickly without lifting equipment.
Another approach is disclosed in U.S. Pat. No. 3,944,187 (Walker). With this approach an array of energy-absorbing elements is mounted within a framework that is designed to collapse upon impact. The framework is guided by ground anchors of various types prior to and during a collision. The preparation of the site, including the installation of such ground anchors, makes it difficult to install such crash barriers quickly with limited equipment and personnel.
A third approach is disclosed in U.S. Pat. No. 5,192,157 (Laturner), in which an energy-absorbing device is cantilevered on the end of a barrier. This approach reduces or eliminates the need for ground anchors and the like and thereby speeds installation.
U.S. Pat. No. 4,711,481 (Krage) discloses a lightweight impact attenuating device having folded, sheet metal energy absorbing elements mounted between parallel diaphragms. The Krage patent suggests that the disclosed energy absorbing elements can be used in the system of the Walker patent.
Further improvements are possible, and it would be of great advantage to the industry if a light-weight crash attenuator were available that could be mounted on and removed from the end of a barrier quickly and efficiently with a small number of installing personnel and little additional equipment.